Acuity Index is an open source Substrate event indexer. It helps dapps consume event data through a real-time indexing API.
Since v0.8, we shipped config-driven index specs, explicit query keys, hot reload, reindexing across spec changes, composite/multi-field keys, Prometheus metrics, event proofs, JSON-RPC 2.0, better throughput/reliability, and stronger production safety. v0.9.1 adds simpler subscriptions, cleaner event payloads, top-level timestamps and WS heartbeats.
As far as I understand, Acuity Index is a client that reads runtime events via subxt and indexes them for fast querying. It also pins the indexed data to IPFS, along with an embedded key-value database and a finality prover for events.
As a result, frontend applications that submit extrinsics can query indexed events instead of directly querying on-chain state.
Can you confirm it?
Not exactly. Acuity Index doesn’t use IPFS in any way.
An index spec toml file describes which event keys should be indexed. Dapps or other services can then query the index. The index will hydrate the results with the actual events that were emitted, the timestamp and grandpa proofs.
A dapp may still need to query state directly, but typically everything that a dapp needs can be reconstructed from events.
For example, for basic balance transfers account balances are stored in state, but transfer history is stored in events. You can get the latest balances either by querying state directly or by querying the indexer for the latest transfer events.
I made a big tipper proposal on Polkadot for the latest features:
You can vote here: [Big Tipper] Acuity Index Event Indexer for Polkadot Dapps (1000 DOT)
As someone currently researching the Polkadot ecosystem for a course project, I’m curious about something:
Would tools like this mainly matter for developers building applications on Polkadot, or can infrastructure improvements like this also eventually affect the experience of regular users?